The most important people at the Republican presidential debate

Members of the audience look on as Republican presidential candidates participate in the debate in Sioux City, Iowa, on Dec. 15, 2011.

Reuters photographer Jim Young took the pictures that he had to take at last night's Republican candidates' debate in Sioux City, Iowa. You can see one of them below. But he also turned his camera around to examine the faces of the audience. It's the views of people like these that will matter the most when the Iowa caucus is held on January 3.